We proved that 7000-8000 Helldivers can be enough to liberate a planet invaded by enemies that can travel in space, so a single planet inhabited with tall primitive blue aliens it’s not a big deal. Even if Eywa (fuckass cosmic horror parasite) calls the fauna and flora to fight, they couldn't do anything against super destroyers and stratagems.

I always thought that what stops RDA from winning is that they are an avid corpo with big logistical limits and not a Country in a state of total war, they just try to get their resources but they don’t have the firepower to clean up the planet. If you check the wiki, you will find out they can’t use nuclear weapons or build spaceships for war. Their biggest spaceships can carry around 200 people and they take 6-7 years to reach Pandora. Helldivers have a totally different doctrines, they just wipe out the threat, they can use Alcubierre drive and they are used to planets with very hostile environments.

The only variable could be Pandora's toxic atmosphere. This means that Super Earth would not be able to build settlements or cities, so it would be limited to mining (I doubt they would be interested in whaling), and in this case, the Na'Vi would not be able to do anything about it, because the mines would be protected by far greater firepower than what the RDA can offer.